To meet the demand for wireless data traffic having increased since deployment of 4G (4th-Generation) communication systems, efforts have been made to develop an improved 5G (5th-Generation) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post LTE System’.
The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems.
In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like.
In the 5G system, Hybrid FSK and QAM Modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed.
In the Long Term Evolution (LTE) system, an evolved Node B (eNB) dynamically allocates resources to a user equipment (UE) on a per-sub-frame basis. If semi-persistent scheduling (SPS) is activated, the UE is granted to periodically use resources allocated based on predetermined settings until the SPS is released.
FIG. 1 is a view illustrating an example of an LTE network-based device-to-device (D2D) system according to the related art.
Referring to FIG. 1, the LTE network-based D2D system may come in two communication modes. The two communication modes include in-coverage D2D communication mode and out-of-coverage D2D communication mode.
UEs 102, 104 and 106 are in-coverage mode UEs, and UEs 112 and 114 are out-of-coverage mode UEs. UEs 108 and 110 are partial in-coverage mode UEs.
In in-coverage mode, the resources used for the UE 102 to transmit data and control information are directly scheduled by an eNB 100. In out-of-coverage mode, the resources used for the UE 112 to transmit data and control information are selected by the UE 112 from a resource pool.
FIG. 2 is a view illustrating an example of a structure of a communication frame in a D2D communication system according to the related art.
Referring to FIG. 2, a D2D frame 200 may be divided into a scheduling assignment (SA) region 202 and a data region 204. The SA region 202 is a region where control information is transmitted and may contain multiple control units (resource units used for controlling). In each control unit of the SA region, the UE may transmit an SA indicating a resource to be used for transmission in the data region 204. The data region 204 typically has a length of tens of sub-frames or more. For example, the data region 204 may be 40 ms to 160 ms long.
The resource allocation scheme in LTE cannot be directly applied to D2D communication. Accordingly, a need exists for designing a resource allocation mechanism and signaling for LTE network-based D2D systems.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.